Fast Sausage Oscillations in Coronal Loops with Fine Structures

Extended AbstractThe Kwasan and Hida Observatories team (three of the authors but A. T.) observed the total solar eclipse of 11 July, 1991 with the multi-channel telescope at UABCS (Universidad Autonoma de Baja California Sur) campus in La Paz, Baja California Sur, Mexico. The primary purpose of our obsevation is to get high-resolution images of the inner corona at the wavelength of coronal emission lines and continuum shown in Table 1. Thanks to the clear sky and good seeing condition, we successfully got many images of high spatial resolution with photographic cameras and video recorders. Details of the observation have already been published by Kurokawaet al. (1992). In this paper, we present the results obtained from the photographic data reduction on fine structures of the inner corona. The procedure of photometrical measurement and image processing are fully described in another paper (Takeda, 1993).There have been published several observational works on the temperature structure of the coronal loops. Some authors proposed that hot coronal loops have cool cores (Foukal, 1975; Hanaokaet al., 1988), but others denied such coaxial models (Chenget al., 1980; Dere, 1982). Our high-resolution images obtained at the eclipse enables us to compare the positions of the loops seen in different emission lines of different ionization temperatures more precisely than any other previous observations. Main results are summarized as follows.

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Structure and Equilibrium of Coronal Magnetic Fields

Symposium - International Astronomical Union ◽

10.1017/s0074180900088148 ◽

1990 ◽

Vol 142 ◽

pp. 303-308

Author(s):

A. A. Van Ballegooijen

Keyword(s):

Velocity Field ◽

Coronal Loop ◽

Spatial Scales ◽

Simplified Model ◽

Coronal Loops ◽

Magnetic Structures ◽

Coronal Magnetic Fields ◽

Fine Structures ◽

Field Lines ◽

Coronal Field

In “closed” magnetic structures (i.e., coronal loops) the random shuffling of magnetic footpoints in the photosphere causes twisting and braiding of field lines in the corona. If the motions are sufficiently slow, the coronal field evolves through a sequence of force-free equilibrium states. Numerical simulations are presented for a simplified model in which the overall curvature of the coronal loop is neglected. It is shown that magnetic fine structures develop on spatial scales significantly smaller than those of the imposed “photospheric” velocity field.

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Magnetic Fine Structures in Coronal Loops

Mass Supply and Flows in the Solar Corona ◽

10.1007/978-94-011-0930-7_5 ◽

1994 ◽

pp. 31-35

Author(s):

A. A. Van Ballegooijen

Keyword(s):

Coronal Loops ◽

Fine Structures

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Siphon Flows in Stratified Coronal Loops

International Astronomical Union Colloquium ◽

10.1017/s0252921100025288 ◽

1994 ◽

Vol 144 ◽

pp. 185-187

Author(s):

S. Orlando ◽

G. Peres ◽

S. Serio

Keyword(s):

Heat Flux ◽

Scaling Laws ◽

Flow Model ◽

Supersonic Flows ◽

Coronal Loops ◽

Characteristic Parameters

AbstractWe have developed a detailed siphon flow model for coronal loops. We find scaling laws relating the characteristic parameters of the loop, explore systematically the space of solutions and show that supersonic flows are impossible for realistic values of heat flux at the base of the upflowing leg.

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Ultrastructure of NPC/HK1 cells heterotransplanted in athymic nude mice

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010005384x ◽

1982 ◽

Vol 40 ◽

pp. 236-237

Author(s):

E.C. Chew ◽

C.L. Li ◽

D.P. Huang ◽

H.C. Ho ◽

L.S. Mak ◽

...

Keyword(s):

Cell Line ◽

Nude Mice ◽

Biopsy Specimen ◽

Epithelial Cell Line ◽

Present Communication ◽

Recurrent Tumour ◽

Athymic Nude Mice ◽

Cell Line Establishment ◽

Fine Structures ◽

Well Differentiated

An epithelial cell line, NPC/HK1, has recently been established from a biopsy specimen of a recurrent tumour of the nasopharynx which was histologically diagnosed as a moderately to well differentiated squamous cell carcinoma. A definite decrease in the amount of tonofilaments and desmosomes in the NPC/HK1 cells during the cell line establishment was observed. The present communication reports on the fine structures of the NPC/HK1 cells heterotraneplanted in athymic nude mice.

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Oxygen K near edge structures studied with multiple scattering calculations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104583 ◽

1988 ◽

Vol 46 ◽

pp. 504-505

Author(s):

Xudong Weng ◽

Peter Rez

Keyword(s):

Cross Section ◽

Cross Sections ◽

Partial Cross Section ◽

Energy Window ◽

Edge Structure ◽

Fine Structures ◽

Hydrogenic Model ◽

Electron Energy Loss ◽

Quantitative Chemical

In electron energy loss spectroscopy, quantitative chemical microanalysis is performed by comparison of the intensity under a specific inner shell edge with the corresponding partial cross section. There are two commonly used models for calculations of atomic partial cross sections, the hydrogenic model and the Hartree-Slater model. Partial cross sections could also be measured from standards of known compositions. These partial cross sections are complicated by variations in the edge shapes, such as the near edge structure (ELNES) and extended fine structures (ELEXFS). The role of these solid state effects in the partial cross sections, and the transferability of the partial cross sections from material to material, has yet to be fully explored. In this work, we consider the oxygen K edge in several oxides as oxygen is present in many materials. Since the energy window of interest is in the range of 20-100 eV, we limit ourselves to the near edge structures.

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ELNES of Iron Compounds

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133734 ◽

1990 ◽

Vol 48 (2) ◽

pp. 28-29

Author(s):

Hiroki Kurata ◽

Kazuhiro Nagai ◽

Seiji Isoda ◽

Takashi Kobayashi

Keyword(s):

Energy Loss ◽

Metal Ions ◽

Energy Resolution ◽

Transition Metal Oxides ◽

Local Symmetry ◽

Iron Compounds ◽

Fine Structures ◽

Electron Energy Loss ◽

Fe Ions ◽

Electron Energy Loss Spectra

Electron energy loss spectra of transition metal oxides, which show various fine structures in inner shell edges, have been extensively studied. These structures and their positions are related to the oxidation state of metal ions. In this sence an influence of anions coordinated with the metal ions is very interesting. In the present work, we have investigated the energy loss near-edge structures (ELNES) of some iron compounds, i.e. oxides, chlorides, fluorides and potassium cyanides. In these compounds, Fe ions (Fe2+ or Fe3+) are octahedrally surrounded by six ligand anions and this means that the local symmetry around each iron is almost isotropic.EELS spectra were obtained using a JEM-2000FX with a Gatan Model-666 PEELS. The energy resolution was about leV which was mainly due to the energy spread of LaB6 -filament. The threshole energies of each edges were measured using a voltage scan module which was calibrated by setting the Ni L3 peak in NiO to an energy value of 853 eV.

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EXELFS Studies of Carbon Fibers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100133953 ◽

1990 ◽

Vol 48 (2) ◽

pp. 72-73

Author(s):

V. Serin ◽

K. Hssein ◽

G. Zanchi ◽

J. Sévely

Keyword(s):

Carbon Fibers ◽

Energy Analysis ◽

Electron Excitation ◽

Complex Structures ◽

High Modulus ◽

Promising Technique ◽

X Ray ◽

Fine Structures ◽

X Ray Absorption

The present developments of electron energy analysis in the microscopes by E.E.L.S. allow an accurate recording of the spectra and of their different complex structures associated with the inner shell electron excitation by the incident electrons (1). Among these structures, the Extended Energy Loss Fine Structures (EXELFS) are of particular interest. They are equivalent to the well known EXAFS oscillations in X-ray absorption spectroscopy. Due to the EELS characteristic, the Fourier analysis of EXELFS oscillations appears as a promising technique for the characterization of composite materials, the major constituents of which are low Z elements. Using EXELFS, we have developed a microstructural study of carbon fibers. This analysis concerns the carbon K edge, which appears in the spectra at 285 eV. The purpose of the paper is to compare the local short range order, determined by this way in the case of Courtauld HTS and P100 ex-polyacrylonitrile carbon fibers, which are high tensile strength (HTS) and high modulus (HM) fibers respectively.

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Further studies on the ultrastructure of the cochlea

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100159746 ◽

1990 ◽

Vol 48 (3) ◽

pp. 440-441

Author(s):

Zhixian Wang ◽

Pinjin Zhu ◽

Jianhe Sun ◽

Xuezheng Song

Keyword(s):

Hair Cells ◽

Military Medicine ◽

Outer Hair Cells ◽

Apical Surface ◽

Epithelial Surface ◽

Hearing Research ◽

New Findings ◽

Fine Structures ◽

Temporal Bones ◽

Accurate Observation

Hearing research is important not only for clinical, professional and military medicine, but also for toxicology, gerontology and genetics. Ultrastructure of the cochlea attracts much attention of electron microscopists, (1―3) but the research lags far behind that of the other parts of the organnism. On the basis of careful microdissection, technical improvment and accurate observation, we have got some new findings which have not been reported in the literature.We collected four cochleas from human corpses. Temporal bones dissected 1 h after death and cochleas perfused with fixatives 4 h after death were good enough in terms of preservation of fine structures. SEM:The apical surface of OHCs (Outer hair cells) and DTs (Deiters cells) is narrower than that of IPs (Inner pillar cells). The mosaic configuration of the reticular membrane is not typical. The stereocilia of IHCs (Inner hair cells) are not uniform and some kinocilia could be seen on the OHCs in adults. The epithelial surface of RM (Reissner’s membrane) is not smooth and no mesh could be seen on the mesothelial surface of RM. TEM.

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